Accurate force fields and methods for modelling organic molecular crystals at finite temperatures

作者:Nyman Jonas; Pundyke Orla Sheehan; Day Graeme M
来源:Physical Chemistry Chemical Physics, 2016, 18(23): 15828-15837.
DOI:10.1039/c6cp02261h

摘要

We present an assessment of the performance of several force fields for modelling intermolecular interactions in organic molecular crystals using the X23 benchmark set. The performance of the force fields is compared to several popular dispersion corrected density functional methods. In addition, we present our implementation of lattice vibrational free energy calculations in the quasi-harmonic approximation, using several methods to account for phonon dispersion. This allows us to also benchmark the force fields' reproduction of finite temperature crystal structures. The results demonstrate that anisotropic atom-atom multipole-based force fields can be as accurate as several popular DFT-D methods, but have errors 2-3 times larger than the current best DFT-D methods. The largest error in the examined force fields is a systematic underestimation of the (absolute) lattice energy.

  • 出版日期2016-6-21

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